The production of beer requires great amounts of energy. To this end, mainly primary energy is used and degraded, with the simultaneous formation of CO2. Especially the mashing process and the wort-boiling process require great amounts of energy.
In order to reduce the use of primary energy, it was already attempted in the past to recover energy and reuse it elsewhere in the process. An important example is here the recovery of energy from vapors, which arises during the boiling of wort and which is then used again for preheating the wort in the next brewing process.
After the thermal treatment, e.g. the boiling the wort, the wort has a maximum temperature, and is then cooled down to the pitching temperature (e.g. <15° C.). To this end, different facilities and systems are used. The cooling of the hot wort to the pitching temperature may be accomplished by means of plate heat exchangers. Fresh water, or fresh water (ice water) cooled down, for example, to 6° C., is then preferably heated to 75 to 88° C. The heated water is then subjected to further use, for example in the brewing water tank, e.g. for mashing or sparging.
The hot brewing water produced during the above-described cooling of the wort exceeds in many cases the hot water demand of the whole brewery. Especially in hotter regions, or toward the middle or end of the production week, there is a clear hot water surplus in the brewing water tank. Frequently, the brewing water tank contains so much energy that hot water has to be discarded through the gully. If draining of a large amount of hot water through the channel is impossible or not permitted, the hot water amount produced during the cooling of the wort has to be reduced (cooled down) with a great use of energy (mainly electric energy) by employing a cooler. Hence, it is not surprising that the refrigeration plant accounts for approximately 40% and more of the total current demand of a brewery. Summarizing, it is noted that the known methods involve a destruction of valuable resources due to the partly massive overproduction of hot water and the high expenditure in terms of system engineering and energy required for the removal thereof, as the hot water surplus can only be removed by using a great amount of energy and/or by destroying an enormous amount of heat, along with the wastage of fresh water. Hence, the known methods show great deficiencies with respect to energy efficiency and environmental friendliness.
Also, greater amounts of raw fruit or decoction mash or, respectively, amounts of mash whose hot temperature is maintained, frequently hold a great amount of energy which is not utilized and needs to be carried off.